This invention relates to imprinting systems, such as, postage meter mailing machine, which systems are used to imprint information on a sheet-like medium and, more particularly, to an imprinting system where the information imprinted on the sheet-like medium is correlative to a variable parameter of the medium, such as, imprinting a postage value indicia on a envelope wherein the postage value is correlative to the weight of the envelope.
In the mail processing field, it is most desirable for a system operator to be able to deliver to mail processing equipment a batch of "mixed mail", that is a batch comprised of a large number of envelopes of varying dimensions, particularly thickness and weight. The ability of a mail processing system to process a large variety of mixed mail eliminates the need for the system operator to perform the preliminary steps of presorting the mail. It is further desirable for mail processing equipment to be able to weigh the individual envelopes and affix the appropriate postage value indicia in accordance with the envelope weight. It is generally considered advantageous if the mail processing equipment can imprint a quality indicia upon envelopes varying in thickness from that of a postcard to approximately one quarter (1/4) of an inch.
It is known to provide mail processing equipment comprised of a feeder for singularly delivering envelopes in series to a transport assembly. The transport assembly deposits each envelope on the scale for weighing. After a sufficient time to assure a true scale reading of the envelope weight, commonly referred to as "weigh on the pause", the transport assembly again assumes control over the envelope and delivers the envelope to the mailing machine.
The mailing machine is most commonly comprised of an integral transport assembly and attached rotatory print drum type postage meter. The mailing machine transport assembly assumes speed control over the envelope performing any necessary speed adjustments to the envelope required to match the envelopes traversing speed with the imprinting speed of the postage meter print drum to promote a quality indicia print. It is known for the postage meter to include a value setting mechanism operating under the influence of the scale, which causes the postage meter value setting mechanism to adjust the postage meter printing mechanism for printing of the appropriate postage rate on the approaching envelope according to the envelope weight as determined by the scale.
The mail processing system depicted above has as its primary objectives (i) the capability to process a wide variety of envelopes (particularly with respect to thickness and weight) (ii) as fast as possible (in terms of envelopes per second) (iii) while applying a quality postal indicia.
The described mail processing system has several limiting factors with respect to increasing throughput relative to system cost. One such limiting factor is represented by the time required in transporting the envelopes from one process station to another. Another limiting factor is reflected in the time necessary to obtain an accurate weight from the scale. While such factors as transport time and weighing time can conceivably be decreased by incorporating advanced system techniques, the rule of diminishing returns predicts that small improvements in system throughput by such an incorporation would be achievable only with disproportionate increases in system cost.
One possible alternative means of increasing the throughput of such mail processing systems is to provide multiple scales and a suitable transport system such that the scales are placed in alternative use. Such an arrangement would conceivably allow overlapping of system process or function to achieve a significant increase system through. However, such an alternative represents added cost from both an equipment and system complexity standpoint.